Moon Lander: How We Developed the Apollo Lunar Module (38 page)

NASA’s concern was so great that after a month of inspection and tests at KSC, they had George C. White, chief of Reliability and Quality Assurance at NASA Headquarters, personally inspect LM-3 and review all the findings. He identified nineteen areas in which the craft had quality problems requiring evaluation by the Certification Review Board before clearance for flight. The resulting uncertainty over when LM-3 would be ready for flight caused NASA to consider alternative missions to prevent too long a gap between launches. The first manned orbital flight of command and service modules, Apollo 7, was scheduled for October 1968, to be followed by a manned CSM/LM flight demonstrating rendezvous in Earth orbit in December. George Low proposed delaying the latter mission because LM-3 would not be ready and substituting a CSM-only lunar-orbit mission. He sold this idea to the NASA hierarchy, and it was officially adopted.
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Air force Brigadier General Carroll H. “Rip” Bolender, LM program manager at NASA-Houston, announced the decision to us in Bethpage. I was embarrassed that NASA had to improvise a mission because our LM was not ready, but I was thrilled with the mission they chose. Orbiting the Moon at Christmastime with Apollo 8 seemed an inspired choice, and it would settle some nagging concerns about the accuracy of lunar-orbit navigation in the complex, “lumpy” gravitational field of the Moon.
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General Bolender told us NASA wanted Grumman people to observe the mission support operations on the new mission, designated Apollo 8, as preliminary training for our first manned mission. When the time came, John Coursen, Bob Carbee, Arnold Whitaker, and other key engineers observed mission support operations on Apollo 8 in Houston. I stayed in Bethpage to coordinate solutions to problems with predelivery operations on LM-5 and LM-6 and to make prelaunch preparations for LM-3 and LM-4 at KSC.

LM-3 continued to have problems, especially wire breakage. George Low dispatched Martin L. Raines, Reliability and Quality Assurance chief at Houston, to KSC in January 1969 to assess how bad its wiring was. He found hundreds of wire splices and repairs but considered them safe, and the spacecraft was fully functional and continued to pass its operational checkout procedures. In the other major problem area, stress corrosion, Grumman inspected more than fourteen hundred components on LM-3 to LM-8 and replaced any with cracks. Some of the structural tubes of 7075-T6 aluminum alloy were replaced with the more corrosion resistant 7075-T73 temper. At the LM-3 design certification review at NASA Headquarters in early January, all previously identified issues were declared resolved. The prime crew made their own investigation of LM-3’s status, and at the flight readiness review at KSC in mid-February
they concurred that her quality was satisfactory, and she was ready for flight.
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I traveled to Houston to take part in mission simulations of Apollo 9. These were more complex and realistic than for the unmanned Apollo 5, since in addition to the flight controllers in the Mission Operations Control Room (MOCR), the stations of the worldwide Manned Spaceflight Network (MSFN), the contractors in the Spacecraft Analysis (SPAN) Room and the Mission Evaluation Room, and other ground-support personnel, they included the astronauts flying the command module and lunar module mission simulators. From my station in the windowless SPAN Room, across the hall from the darkened, theaterlike MOCR with its rows of flight controllers intently gazing at the greenish displays on their cathode ray tube (CRT) consoles, it was indistinguishable from the real thing. I saw the same LM instrumentation readings on the CRT and heard the same network protocols over my headset as in an actual mission, including communication acquisition and loss of signal as the orbiting spacecraft entered and left the range of each ground tracking station, and the capsule communicator (CapCom) conversing with the flight crew. The CapCom, himself an astronaut, was the only person on the net allowed to directly communicate with the crew; all messages from the ground were relayed by him.

Once during a simulation of Apollo 9 this carefully contrived virtual reality was shattered abruptly. During a quiet period in the mission, the LM (mission call-name Spider) failed to reacquire communications with the tracking station at Woomera, Australia, after passing over the Indian Ocean and the Australian outback. The ground team began analyzing the LM’s communications systems and could see no problem. Since Spider was flying formation at a distance with CM Gumdrop, CapCom asked Dave Scott, the CM pilot, to hail Spider using Gumdrop’s radio. Scott hesitated and delayed for several minutes in following through on the request. Then Comdr. Jim McDivitt’s voice came sheepishly over the net: “I’m sorry fellows; you caught us. Rusty and I sneaked out for a few minutes to get a sandwich; we thought we’d make it back before acquiring the next ground station. Sorry about that!”

The simulations allowed us to practice our assigned roles and sharpen our real-time problem-solving skills. As the senior Grumman representative, my job in SPAN was to evaluate each LM problem as it arose and to marshall as much expert help in the solution as time allowed. I collected their inputs, made my own evaluation, and presented this to the NASA senior person in SPAN (usually Owen Maynard or Scott Simpkinson) as Grumman’s official recommendations. Any deviation from normal performance was called an anomaly, and each anomaly was written up on a discrepancy report form as it occurred and dispositioned when the explanation of the cause was agreed upon. This might occur weeks later, after extensive computer analyses or laboratory tests had been performed.

The last mission simulation I took part in was about two weeks before scheduled launch. By then we were part of a finely honed mission support team, ready to assist the NASA flight director and his flight controllers in dealing with the unexpected as it came up in flight. We knew the astronauts’ lives would be depending upon LM for the first time in space.

Apollo 9 was also LM’s first flight together with the command and service modules. It was an ambitious ten-day mission with the goal of performing in Earth orbit the entire sequence of events required on a lunar mission, except for the actual landing. It also provided the first and only flight test of the spacesuit and backpack to be used in exploring the Moon, during extravehicular activity, or spacewalks, from both the LM and the CM.

You Have Twenty Minutes …

Before it was even launched Apollo 9 provided one of the most difficult tests of my ability to assess conflicting data and provide NASA with a sound recommendation. About four hours before scheduled liftoff at KSC, an anomaly was noticed during prelaunch filling of the LM’s descent helium tank. The helium was used to pressurize the descent propellant tanks, causing the fuel and oxidizer to flow into the rocket engine without pumps. To minimize tank weight, the helium was stored at high pressure and extremely low temperature (nominally 1,540 pounds per square inch at minus four hundred degrees Fahrenheit), which put it in what thermodynamicists call the supercritical state, where it is as dense as a liquid and yet completely fills its container like a gas. This required a tank of advanced design with a highly effective vacuum jacket and insulation, made for us by the Airesearch Division of Garrett Corporation. When filling the tank the servicing crew weighed the amount of helium delivered and verified the tank’s thermal performance by reading the predicted combination of temperature and pressure from a thermodynamic chart.

When Spider’s helium tank was loaded, the resulting temperature and pressure fell above the predicted curve, suggesting that excess heat was leaking into the helium. Since this could be caused by an insulation defect in the helium servicing cart or its vacuum-jacketed hoses as well as the flight tank, our first recommendation was to empty the flight tank and refill it, using a different servicing cart and hose set. I was at my post in the SPAN Room at the Mission Control Center in Houston discussing the problem with the NASA propulsion people there, as well as on the phone with our Grumman people at KSC. It took more than an hour to detank and refill, and although the result was somewhat improved over the previous, it was not quite within limits. We decided to wait half an hour and see what happened, reasoning that if there were an insulation defect in the tank it should continue to pick up excess heat and move farther from the allowable curve. Instead of moving away
from allowable, the pressure/temperature combination drifted toward it and forty-five minutes later was within limits.

It was the worst kind of anomaly; a discrepancy that corrects itself! Is it the hidden clue to a real problem with the hardware, or just a minor and meaningless aberration in a system so complex that all of its variations may never be understood? If the tank really had a heat leak we should scrub the launch and change it, because otherwise we could not be sure of conducting all the descent engine firings required by the mission. It would delay the launch by about five days.

George Low, NASA’s Apollo spacecraft director, came into the SPAN Room himself to confer directly with me and Owen Maynard, NASA’s LM Engineering manager. This showed the gravity of the situation, since I had never seen him in SPAN before. Low was a careful, thorough engineer and a decisive manager; he had led the Apollo program’s technical rebuilding after the dark days of the Apollo 1 fire. After we briefed him on the helium anomaly, he fixed his steely blue eyes on me and asked for Grumman’s recommendation: Did we proceed with the launch or scrub and change the tank? He said I had twenty minutes to let him know.

I spent most of the twenty minutes on the phone with people who could contribute to the decision, including Grumman’s corporate chief engineer, Grant Hedrick, who had a sixth sense for pinpointing the cause of technical problems, and the experts at Airesearch, who had searched all prior test records on that tank and found no anomalies. Then I went up to the VIP viewing area behind Mission Control and huddled in a corner of the dimly lit room with Joe Gavin. Summarizing the data and the tradeoffs, I recommended to Gavin that we launch. After a thoughtful pause, he concurred. I hurried back to the SPAN Room and repeated this recommendation to Owen Maynard. When he agreed as well, I called George Low and told him that Grumman officially recommended that NASA proceed with the launch, as we believed the tank to be sound. He asked what Gavin and Hedrick thought. I said they agreed, and Low then said NASA would proceed with the launch. He thanked me for meeting my deadline.

NASA did not mention the issue for the remainder of the mission, but I monitored the helium tank’s performance almost continuously whenever it was accessible on the screen.

A Great Flying Machine

Nothing that followed in the actual flight put so much pressure on me personally, and for the most part the flight went well. It was our Grumman support team’s first direct experience with astronauts on a real mission, and I found it exciting to have men whom I knew up in space flying our machine. The giant three-stage Saturn 5 booster lifted off on schedule and performed
flawlessly except for some Pogo longitudinal vibrations in the S2 stage, placing the spacecraft into exactly the planned Earth orbital altitude. The critical maneuvers of command and service module separation from the spacecraft/LM adapter, and rotation and docking to the LM, went perfectly. Upon command the LM was separated and pulled away by the CSM, while the S4B stage was jettisoned into a lower orbit and burnup in the Earth’s atmosphere. After six hours of checking out the CSM and its systems, McDivitt fired the service propulsion system (SPS), and the powerful rocket engine boosted the heavily laden CSM/LM combination into a higher orbit. He sounded relieved that the dormant LM was still there after the force of the first burn. Three additional SPS firings were successfully accomplished, increasing the crew’s confidence in the capability of their spacecraft. Following these operations the crew settled down for a meal and sleep; the first Apollo mission on which the three astronauts were allowed to sleep simultaneously. I took advantage of the quiet time and shift change to hand the SPAN duty over to Howard Wright.

I was back to the SPAN Room early the next morning, listening to the crew puffing as they donned their spacesuits to enter the LM. The crew channel went dead. We did not learn until the postflight briefings that Schweickart had suddenly vomited.
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After some delay he entered the LM and flipped dozens of switches to activate its systems. He commented that the LM was quite noisy, particularly its environmental control system. McDivitt joined him, and after they unpacked the television camera in the LM cabin we watched them on worldwide TV. Our friend McDivitt promptly embarrassed us by pointing out to the world a washer and other bits of manufacturing debris floating through the cabin under zero gravity. It was a chastisement we deserved, and it motivated us to still more stringent efforts to clean the cabin and all closed compartments of the LM during assembly and test.

McDivitt and Schweickart extended the LM’s landing gear, which locked smartly into place upon command. They checked out the LM’s systems and fired the LM descent engine for more than six minutes at full thrust while in the docked condition, simulating much of the powered descent burn that would be required to bring LM down from lunar orbit for landing. The crew controlled the engine manually and demonstrated digital autopilot attitude control.
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All LM operations went perfectly, including the performance of the suspect descent helium pressurization system. When McDivitt and Schweickart rejoined Dave Scott in the command module, they felt that their LM would be up to the challenges ahead.

The fourth day in orbit all three astronauts donned their space suits and opened the hatches of both spacecraft. Schweickart and Scott performed spacewalks from the LM and the CM respectively; the former using his backpack
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for space life support, while Scott and McDivitt’s spacesuits were connected to their spacecraft by flexible umbilical hoses. Unknown to us, Schweickart was instructed to take the spacewalk a step at a time and end the
exercise immediately if he felt nauseous. Plans for him to float freely in space on his tether were dropped, but he did use the handholds to climb up the front face of the LM ascent stage near the docked connection between Spider and Gumdrop, where he could clearly see Dave Scott standing in Gumdrop’s open hatchway. He and Scott photographed each other in their celestial perches like ordinary tourists. During the spacewalk Schweickart went by the call name Red Rover since he was a third spacecraft himself, communicating through the backpack’s radio. Although its duration was halved to one hour, the spacewalk and backpack demonstration were completely successful.